Samantha Power presents credentials as new US ambassador to UN chief Ban Ki-moon

UNITED NATIONS — Samantha Power presented her credentials as U.S. ambassador to the United Nations to Secretary-General Ban Ki-moon on Monday, stressing the critical link between the global superpower and the world body.

The former foreign policy adviser to President Barack Obama told reporters before the ceremony that she was honored, thrilled and "incredibly fortunate to be able to come to New York to sit behind the placard that says the United States."

"I've worked with the secretary-general over the last few years at the White House, worked very effectively with him and I'm looking very much forward to a close working relationship now that I am up here in New York," she said.

Power was sworn in Friday by Vice President Joe Biden, a day after the Senate overwhelmingly approved her nomination by a vote of 87-10. She succeeds Susan Rice, now the president's national security adviser.

At age 42 and 10 months, Power is the youngest-ever U.S. ambassador to the United Nations. The U.S. Mission said she is a month younger than Donald McHenry was when he was confirmed as ambassador by the Senate in September 1979.

The Irish-born Power, a one-time journalist who also has a Harvard Law School degree, has reported from many of the world's trouble spots and won a 2003 Pulitzer Prize for a book on the meek U.S. response to many 20th century atrocities, including those in Rwanda and Bosnia in the 1990s. She is an outspoken human rights advocate and has long backed intervention — including military force — to halt human rights violations.

Power reiterated Monday what she told the U.S. Senate during her confirmation hearing — "the United Nations is critical to a range of U.S. interests, and U.S. leadership at the United Nations is indispensable to making progress on those interests."

"Whether its terrorism or the broader range of security concerns, mass atrocities in Syria, South Sudan, the effort to alleviate global poverty, the crackdown on civil society around the world — there are just so many issues where the United States and the United Nations have to work together to achieve progress," she said.

Before handing over her credentials, Power posed for pictures with Ban, and then with her husband, Cass Sunstein, a former Obama administration official, and Ban's wife. They then went into the secretary-general's office for private talks.

Power's penchant for outspokenness has created some problems.

In 2002, she called for a "mammoth protection force" to prevent Middle East violence, a position from which she has distanced herself.

Last month, Venezuela said it was calling off efforts to restore normal relations with the U.S. after she said at her Senate confirmation hearing that the South American country was guilty of a "crackdown on civil society." She also called the U.N.'s inaction to end the large-scale killing in Syria's civil war "a disgrace that history will judge harshly."

In 2008, she resigned as an adviser to Obama's presidential campaign after calling then-rival Hillary Clinton a "monster."